Process and apparatus for covering the energy needs of communities using organic waste

ABSTRACT

A process and relating apparatus is provided which aim at producing industrially usable resultants from hydrocarboneous materials such as used rubber, plastic and municipal waste. The waste is subjected to oxygen-free pyrolysis in the presence of zeolite type catalyst during which gaseous and liquid hydrocarbons are produced with the process being tilted towards producing significantly more from the latter. The gaseous and liquid resultants are preferably further used via burning to provide heat for the pyrolysis and via combustion to generate electricity for preferred purposes respectively.

FIELD OF INVENTION

The present invention discloses a process and relating apparatus for deriving industrially usable resultants from hydrocarboneous materials.

BACKGROUND OF THE INVENTION

The proliferation of various hydrocarbon-based materials experienced today causes enormous problems after their industrial or commercial life cycles come to an end. Landfills do not provide a convenient solution owing to their limited capacity and the environmental pollution risk they inevitably pose. To circumvent these problems various methods employing different types of thermal destruction processes are used to obtain industrially usable products from aforementioned materials. The types of feedstock these methods are able to expediently transform vary from biomass through waste plastic to rubber or to the mixture thereof.

A special kind of thermal destruction process, named pyrolysis, takes place in an oxygen-free environment and makes use of the propensity for chemical transformation of carbonaceous feedstock subjected to elevated temperatures. The type and quality of the products gained are highly dependent on the characteristics of the process (temperature, pressure, residence time) as well as on the catalyst(s) used.

DESCRIPTION OF RELATED ART

U.S. Pat. No. 5,744,668 teaches a method for preparation of gasoline diesel and carbon black with waste rubber and waste plastics. The method involves transformation of the feed material in two steps: after the pyrolysis catalytic cracking is conducted in the presence of zeolite type catalyst to allow lighter hydrocarbons to form.

U.S. Pat. No. 6,835,861 discloses a low energy method of pyrolysis of hydrocarbon materials. The hydrocarbon material is heated while maintaining a vacuum, using a clay catalyst. The temperature of the reaction chamber and the corresponding feedstock input can be varied either over time or spatially within the reaction chamber.

The method and system described in U.S. Pat. No. 8,845,771 uses waste plastic, municipal waste and rubber as feedstock and converts them into a fuel via synthesis gas as an intermediate product.

Summarizing the existing related art, there are pyrolysis methods patented to transform mixed hydrocarboneous feed material into combustible gas and fuel employing zeolite type catalyst at one phase of the thermal destruction. These methods however fail to excel in low residence time, the ability to achieve a self-sustaining process and gaining high-quality resultants applicable immediately to energy generation. Neither does any prior art apparatus offer a solution for treating waste material near to landfills or dumps making transportation of these materials unnecessary.

The object of the present invention is to provide a process which allows suitable treatment of hydrocarbon-based materials such as rubber, plastic and municipal waste for obtaining industrially usable liquid and gaseous end products suitable for further industrial uses immediately, and the system to be designed to be continuous in terms of material flow as well as electricity generation. A further object is to efficiently replace landfills and provide a solution for getting rid of certain otherwise not easily degradable waste types while generating energy carriers available for various purposes. Another object is to make the system closed thus minimizing environmental pollution and maximizing energy efficiency by ensuring that the not fully transformed part of the feedstock gets recycled reducing the amount of residue to a minimum, while complying with all the regulations applicable to the emission of noxious substances. A further object is to make the process not require huge amount of water for either the pyrolytic reaction or the cooling of the apparatus, furthermore, to put to use even the waste heat created during the process by making the cooling water flow available elsewhere for heating. The object of the present invention with regards to the apparatus is to be adapted to an optimized conduction of said process while being of a size that makes its transportation viable being mobile and consisting of modules that allows apparatuses with various dimensions to be built.

These objects are achieved by means of the process and the apparatus having the features indicated in any of the claims set forth below.

DETAILED DESCRIPTION OF THE INVENTION

Advantages and characteristics of the present invention will be apparent from the following detailed description.

Present invention discloses a process for converting hydrocarboneous feed material into liquid and gaseous hydrocarbons suitable for further processing via pyrolysis. The pyrolysis is conducted in the presence of zeolite type catalyst in an oxygen-free environment and comprises the following steps:

mixing the feed material with zeolite type catalyst in the absence of ambient air, subjecting the mixture to pyrolysis in three steps whereby different phases of the thermal destruction occur successively but separately in terms of space and time, removing the gaseous products evolved during the pyrolysis, condensing at least a portion of the evolved gases, removing the solid residue left over from the pyrolysis.

The process runs continuously.

Aforementioned hydrocarboneous feed material comprises plastic, rubber and municipal solid waste, or combinations thereof and shredded to less than 50 times 50 mm cuttings prior to mixing it with zeolite type catalyst amounting to 3-5% relative to its total weight.

The pyrolysis is performed at a temperature from about 450 to 650 degree C. under a pressure of between about −300 Pa and about 300 Pa. for about 10 minutes to about 30 minutes.

During the process the mixture of the feed material and the catalyst are moved spatially.

The characteristics of the process can be controlled in such a way to allow for expedient treatment of various feed materials.

From the condensed gases various hydrocarbon fractions are separated based on different boiling temperature range. The fractions are treated with filters and centrifugal separators to achieve greater purity. Suitable fractions may be subjected to further conversion to create products with desired characteristics or/and used for electricity production. Water can be introduced as a medium for transferring the heat evolved during the electricity production.

Different hydrocarbon fractions are stored separately and the sludge subsided during the storage is recycled as feed material.

The non-condensed gases are preferably burned after cooling to provide heat for the pyrolysis and to produce electricity

The solid residue is subjected to cooling prior to exposing it to the atmosphere.

Moreover, the apparatus for thermal destruction of hydrocarboneous feed material according to present invention comprises a feed material transport module, a pyrolysis reactor and a pyrolysis gas treating module. The feed material transport module includes a hopper which is connected to a feed material conveyor through an airtight inlet. The pyrolysis reactor includes a reaction chamber provided with gas removal outlets which are coupled to the pyrolysis gas line leaving the reactor, an inlet and an air tight outlet for receiving the feed material and removing the residue respectively, a conveyor disposed within the reaction chamber enabling continuous material flow, and a heating means providing heat to the interior of the reactor which is gaseously sealed from the reaction chamber. The pyrolysis gas treating module includes at least one condenser receiving pyrolysis gas from the reactor connected to a pyrolysis oil purification system, and a gas cooler. In the feed material transport module the feed material conveyor connects to a feed material loading conveyor which leads to the pyrolysis reactor inlet and militates against material doming. Three reaction chambers are disposed within the pyrolysis reactor such that the feed material arrives through the reactor inlet in the first reaction chamber, the second reaction chamber receives products from the first reaction camber, the third reaction chamber receives products from the second reaction chamber and the residue leaves the last reaction chamber through the airtight outlet of the reactor.

The operation of the conveyors disposed within the reaction cambers is controllable, whereby the residence time of the feed material in the reaction chambers can be influenced.

The conveyors disposed within the reaction chambers, the feed material conveyor and the feed material loading conveyor are provided in the form of a screw.

The heating means are gas burners.

Each condenser is adapted to condense portions of the pyrolysis gas and thereby separate hydrocarbon fractions with different boiling temperature range. The different fractions are moved through the oil purifications system which consists of oil filters and centrifugal separators and charged into oil storage tanks separately. The storage tanks are connected to the feed material conveyor through a sludge pipe.

The apparatus further includes a gas cooler is adapted to receive non condensed gases from the condensers. The gas burners heating the reaction chambers are adapted to receive non-condensed gas from the gas cooler.

The apparatus further comprises an electricity generation module adapted to receive and be fuelled by hydrocarbons stemming from the pyrolysis. The electricity generation module is preferably a combination of a combustion engine and an electric generator. A water circulation system for cooling the electricity generation module may also be applied.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram is generally illustrative of the abovementioned apparatus.

FIG. 2 is a block diagram is illustrative of the feed material transport module illustrated in FIG. 1.

FIG. 3 is a block diagram is illustrative of the pyrolysis reactor illustrated in FIG. 1.

FIG. 4 is a block diagram is illustrative of the pyrolysis gas processing module illustrated in FIG. 1.

FIG. 5 is a side elevational view of one preferable embodiment of the apparatus illustrated in FIG. 1.

FIG. 6 is a block diagram illustrative of the main steps of the process.

In the embodiment illustrated in FIG. 1, the apparatus includes a gaseosuly sealed feed material transport module (1) that receives feed material from an external shredding unit and mixes the feed material with catalyst before supplying it to a pyrolysis reactor (2). The pyrolysis gas treating module (3) is configured to receive pyrolysis gas from the pyrolysis reactor (2) through a pyrolysis gas line (30) and to separate its components according to their different boiling temperature range. The non-condensed gas component is then supplied to the pyrolysis reactor (2) through a gas recycling line (40) to provide heat for the pyrolysis via burning, and the oil component is charged into oil storage tanks (4). The sludge subsided in the oil storage tanks is recycled as feed material through a sludge pipe (50). From the oil storage tanks suitable liquid fractions are pumped to an electric energy generation module (5) by means of an oil pump (61) through an oil pipe (60). The electric generation module is preferably cooled by water which is suitable for further use in external heating systems. The electric generation module is preferably further connected to an electricity network.

Referring now to FIG. 2, one illustrative embodiment of the feed material transport module (1) illustrated in FIG. 1 is shown. In the illustrated embodiment, the module includes a hopper (21) coupled to an airtight inlet (22). The feed material compounded with catalyst entered the interior of the apparatus is moved forward by a feed material conveyor directing the mixture to a feed material loading conveyor (25) which is in turn in communication with the pyrolysis reactor (2) through a reactor inlet (31 a). The sludge from the oil storage tanks (4) charged onto the feed material conveyor by means of a sludge pump (51) through a sludge pipe (50).

Referring now to FIG. 3, one illustrative embodiment of pyrolysis reactor illustrated in FIG. 1 is shown. In the illustrated embodiment, the pyrolysis reactor (2) includes three reaction chambers (31 a, 31 b, 31 c). Each reaction chamber is provided with an opening (32 a, 32 b, 32 c) for the entry of the feed materials to be processed, a further opening for the exit thereof (33 a, 33 b, 33 c) and a gas removal outlet for the exit of gaseous substances (34 a, 34 b, 34 c). The exit opening of each reaction chamber but the lower one is in communication with the entry of the subsequent reaction chamber. The residue leaves the lower reaction chamber through an airtight outlet (33 c) and is transported further by a residue transport screw (38). A screw (35 a, 35 b, 35 c) is mounted within each reaction chamber along the longitudinal axis thereof allowing for continuous material flow. The gas removal outlets (34 a, 34 b, 34 c) join together in the pyrolysis gas line (30). Heating is provided to the interior of the pyrolysis reactor (37) by gas burners (36) which receive gas from the pyrolysis gas treating module (3) through the gas recycling line (40). The interior of the pyrolysis reactor (37) is gaseously sealed from the reaction chambers (31 a, 31 b, 31 c).

Referring now to FIG. 4, one illustrative embodiment of pyrolysis gas processing module illustrated in FIG. 1 is shown. In the illustrated embodiment, the module includes at least two condensers (41 a, 41 b, 41 c) connected to each other serially so as to the first condenser (31 a) receives pyrolysis gas from the pyrolysis reactor (2) via the pyrolysis gas line (30) and the last one (41 c) is coupled to a gas cooler (42) from which the gas recycling line (40) leads back to the gas burners (36) of the pyrolysis reactor (2). Each condenser (41 a, 41 b, 41 c) is connected to the oil purification system (43) which is adapted to charge the purified hydrocarbons into storage tanks (4 a, 4 b, 4 c).

In FIG. 5 one preferable embodiment of the apparatus is shown. In the figure the numbers used indicate the same elements of the apparatus as in FIG. 1-4.

FIG. 6 is a block diagram illustrative of the main steps of the process in the above mentioned ways.

The process of present invention is conducted during the operation of the apparatus as follows:

The hydrocarboneous feed material comprising plastic, rubber and municipal solid waste, or combinations thereof are shredded to less than 50 times 50 mm cuttings prior to feeding it into the apparatus. The feed material compounded with catalyst in an amount of 3-5% relative to its total weight and loaded into the hopper (21) enters the interior of the apparatus through the airtight inlet (22). Upon reaching the feed material conveyor (23) it is mixed with sludge arriving from the sludge pipe (50) and moved forward to the feed material loading conveyor (25) which charges the mixture into the pyrolysis reactor (2). The presence of more heating means (36) allows obtaining slightly different temperatures in the reaction chambers (31 a, 31 b, 31 c) providing suitable environment for subsequent phases of the thermal destruction process. Due to the rotation of the screws (35 a, 35 b, 35 c) disposed in the reaction chambers (31 a, 31 b, 31 c) the materials processed are pushed forward from the upper openings of the reaction chambers (32 a, 32 b, 32 c) in the direction of the further end of them where the material processed enters the subsequent chamber through suitable formed lower openings (33 a, 33 b, 33 c) The screws can be driven so as to obtain longer residence times coupled with good mixing. The thermal destruction occurs in three phases with the subsequent phases taking place in respectively corresponding reaction chambers.

The pyrolysis is performed at a temperature from about 450 to 650 degree C. under a pressure of between about −300 Pa and about 300 Pa. for about 10 minutes to about 30 minutes.

Nonlimiting examples for the process characteristics required for an expedient treatment of different feedstock:

If the feedstock consists of plastic, it is preferably shredded to less than 10 times 10 mm cuttings and these cuttings are subjected to pyrolysis with a temperature range from 460 degree C. to 480 degree C. for a residence time of between 16 and 18 min.

If the feedstock consists of used rubber, it is preferably shredded to less than 50 times 50 mm cuttings and these cuttings are subjected to pyrolysis with a temperature range from 475 degree C. to 495 degree C. for a residence time of between 18 and 20 min.

If the feedstock is municipal waste containing more than 80% plastic, it is preferably shredded to less than 50 times 50 mm cuttings and these cuttings are subjected to pyrolysis with a temperature range from 475 degree C. to 495 degree C. for a residence time of between 18 and 20 min.

The solid residue leaving the lower reaction chamber through the airtight outlet (32 c) is conveyed forward by the residue transport screw (38) and cooled prior to its exposure to the atmosphere. The solid residue can be further subjected to a magnetic mechanism which separates the carbonaceous char from the steel residue allowing the latter to be recycled.

The gaseous products evolved in the reaction are withdrawn through the gas removal outlets (34 a, 34 b, 34 c) and led via the pyrolysis gas line to the condensers (41 a, 41 b, 41 c). More than two condensers may be serially connected to each other so as to achieve a gradual thermal separation of various hydrocarbons contained in the pyrolysis gas. These way liquid hydrocarbons with different properties can be derived. The liquid fractions are further led from the condensers into a purifying system (43) consisting of centrifugal separators and surface and other filters. During the purification process the liquid fractions are warmed up to adequate temperatures in order to attain viscosities allowing solid contaminants to be relatively easily sequestrated. The purified liquid fractions are filled into storage tanks (4 a, 4 b, 4 c) from which the settled sludge is led back to the feed material transport module through the sludge pipe (50). Non-condensable gaseous products leaving the last condenser (41 c) pass through the gas cooler (42) and are led to the gas burners (36) through the gas recycling pipe (50) to provide heat to the reaction chambers (31 a, 31 b, 31 c). At least part of the liquid fractions stored in storage tanks (4) are pumped through the oil pipe (40) to provide fuel for the electric generation module (5).

The quality of the yields of the process depends on the pyrolysed materials:

In case the feed material consists of plastic, the pyrolysis process typically produces 70 to 75% oil, 15 to 20% non-condensable combustible gas, and 5 to 20% carbonaceous solid residue.

In case the feed material consists of rubber, the pyrolysis process typically produces 35 to 40% oil, 15 to 20% non-condensable combustible gas, 40 to 45% carbonaceous solid residue.

Liquid fractions produced by the process may be subjected to further conversion in which process parameters are so set and various catalysts are so employed to allow creating hydrocarboneous products with desired characteristics.

Lightweight liquid hydrocarbons separated in the gas cooler may be used for cleaning the inner surfaces of the apparatus.

By using the water introduced as a medium for transferring the heat evolved during the electricity production a water circulation system may be created within which the water flows so as to reach gradually higher temperatures via heat exchange with various components of the electric generation module. The water subjected to aforementioned process may be further used for heating.

The portion of the non-condensed gases in excess of the amount necessary for maintaining the pyrolysis may be used to produce electricity.

The apparatus can be so designed and shaped to fulfill practical requirements as to energy output and the amount of waste desired to be processed. Modules with certain dimension can be fabricated allowing communities to cover their entire electricity consumption virtually from their own waste.

ADVANTAGES OF THE INVENTION

The invention has the following advantages:

The invention

-   -   efficiently replaces landfills and provides a solution for         getting rid of certain otherwise not easily degradable waste         types while generating energy carriers available for various         purposes,     -   is closed and aims at minimizing environmental pollution and         maximizing energy efficiency,     -   is designed to be continuous in terms of material flow as well         as electricity generation,     -   ensures that the not fully transformed part of the feedstock         gets recycled reducing the amount of residue to a minimum,     -   complies with all the regulations applicable to the emission of         noxious substances,     -   does not require huge amount of water for either the pyrolytic         reaction or the cooling of the apparatus,     -   avoids creating sound pollution by means of an adequate         insulation,     -   puts to use even the waste heat created during the process by         making the cooling water flow available elsewhere for heating,     -   is mobile and consists of modules that allows apparatuses with         various dimensions to be built. 

What is claimed is:
 1. A process for converting hydrocarboneous feed material into liquid and gaseous hydrocarbons suitable for further processing via pyrolysis, said pyrolysis conducted in the presence of zeolite type catalyst in an oxygen-free environment, comprising mixing the feed material previously shredded to less than 50 times 50 mm with zeolite type catalyst in an amount of 3-5% relative to its total weight in the absence of ambient air, subjecting the mixture to pyrolysis in three steps at a temperature from 450 to 650 degree C. for a residence time of between 10 minutes and 30 minutes while the pressure is maintained between −300 Pa and 300 Pa, continuously moving the feed material mixed with catalyst during the pyrolysis whereby different phases of the thermal destruction occur successively but separately in terms of space and time in three reaction chambers, removing the gaseous products evolved during the pyrolysis, condensing at least a portion of the evolved gases, purifying the condensed gases, storing the purified liquid fractions with different characteristics separately, using at least portion of the purified liquid as fuel for producing electricity, transferring the heat evolved during the electricity production, recycling the sludge subsided during the storage as feed material, cooling the non-condensed gases, burning the non-condensed gases to provide heat for the pyrolysis, removing the solid residue left over from the pyrolysis.
 2. The process according to claim 1, wherein the hydrocarboneous feed material comprises plastic, rubber and municipal solid waste, or combinations thereof.
 3. The process according to claims 1-2, wherein the characteristics of the process can be controlled in such a way to allow for expedient treatment of various feed materials.
 4. The process according to claim 1, wherein condensing at least a portion of the evolved gases comprises: separating various hydrocarbon fractions based on their different boiling temperature range.
 5. The process according to claim 1 wherein purifying the condensed gases comprises using oil filters and centrifugal separators.
 6. The process according to claim 1 further comprising subjecting at least a portion of the liquid fractions to further conversion to create products with desired characteristics.
 7. The process according to claim 1 further comprising using water as a medium for transferring the heat evolved during the electricity production.
 8. The process according to claim 1 further comprising using the portion of the non-condensed pyrolysis gases in excess of the amount needed for providing heat for the pyrolysis for electricity production.
 9. The process according to claim 1 wherein the solid residue is subjected to cooling prior to its exposure to the atmosphere.
 10. An apparatus for thermal destruction of hydrocarboneous feed material comprising a feed material transport module connected to a pyrolysis reactor comprising a reaction chamber and said pyrolysis reactor is coupled to a pyrolysis gas treating module, said feed material transport module comprising a hopper connected to a feed material conveyor through an airtight inlet; said pyrolysis reactor comprising a reaction chamber provided with a gas removal outlet coupled to a pyrolysis gas line leaving the reactor, an inlet and an air tight outlet for receiving the feed material and removing the residue respectively, a conveyor disposed within the reaction chamber enabling continuous material flow, heating means providing heat to the interior of the pyrolysis reactor which is gaseously sealed from the reaction chamber; said pyrolysis gas treating module comprising at least one condenser receiving pyrolysis gas from the reactor and being connected to a pyrolysis oil purification system, Wherein a feed material loading conveyor connecting the feed material conveyor with the pyrolysis reactor inlet is applied for militating against material doming; and three reaction chambers are disposed within the pyrolysis reactor such that the feed material arrives through the reactor inlet in the first reaction chamber, the second reaction chamber receives products from the first reaction chamber, the third reaction chamber receives products from the second reaction chamber and the residue leaves the last reaction chamber through the airtight outlet of the reactor; and said condensers are connected to a gas cooler, said purification system is connected to oil storage tanks, said oil storage tanks are connected to the feed material conveyor through a sludge pipe, and an electricity generation module is adapted to receive fuel from the pyrolysis gas treating module, and the apparatus has a controller means for controlling the characteristics of the process.
 11. An apparatus according to claim 10 characterised in that the operation of the conveyors disposed within the reaction cambers is controllable, whereby the residence time of the feed material in the reaction chambers can be influenced.
 12. An apparatus according to claim 10 characterised in that the conveyors disposed within the reaction chambers are provided in the form of a screw.
 13. An apparatus according to claim 10 characterised in that the feed material conveyor and the feed material loading conveyor are provided in the form of a screw.
 14. An apparatus according to claim 10 characterised in that the heating means are gas burners.
 15. An apparatus according to claim 10 characterised in that each condenser is adapted to condense portions of the pyrolysis gas and thereby separate hydrocarbon fractions with different boiling temperature range.
 16. An apparatus according to claim 10 characterised in that the oil purifications system receiving products from the condensers consists of oil filters and centrifugal separators.
 17. An apparatus according to claims 10 characterised in that gas burners are adapted to receive non-condensed gas from the gas cooler.
 18. An apparatus according to claim 10 characterised in that the electricity generation module is a combination of a combustion engine and an electric generator.
 19. An apparatus according to claims 18 further including a water circulation system for cooling an electricity generation module. 